In computer environments, maximising performance is a key requirement. For example, in an Internet environment, if a user is wishing to download a file, there is a need for a mechanism that prepares data so that a preview of that file can be provided. This allows a user to decide whether or not to download the file. For example, one preparing mechanism provides “thumbnails” for text files (e.g. documents), picture files (e.g. jpegs, gifs etc.) etc. A thumbnail is a miniature version of the file and provides the user with an image overview of the file. This mechanism increases performance, because it is quicker to load a plurality of thumbnails of files, than the files themselves. A user can select the thumbnail in order to view the original file.
Another preparing mechanism is available for an audio file, wherein a preview version of an audio file is prepared, the preview version comprising a small amount of the total audio data of the audio file (e.g. the first few seconds of the audio data). By downloading the preview version, a user can decide whether or not to download the audio file itself. This mechanism increases performance, because downloading the preview version is much quicker than downloading the audio file itself, as the amount of data in the preview version is smaller.